to elecrtic fan the stock IC or not?

Installed in dash.

pretty nifty,

i should be getting my dual spal fans in a day or two so i'll remove ic once again, add my inch spacers and reinstall everything.

should work this time since i'll have that extra wiggle room

Put the banded end of the diode terminal onto the 30 wire for the +12 part of the relay coil, which I guess is going to the alternator terminal.

The unbanded terminal end goes to the other coil terminal which I guess is 85 and your switched ground terminal for the coil.

Just remember that a blown diode or shorted wire to ground will kill your battery pronto by running the fan all the time just like a cheesy delay relay.

I'd run the +12 for the relay coil power to the A/C IGN 3 terminal.

Key would need to be on and in RUN, for the fan to run.

Picked up one of these fancy diodes but don't have a clue as to which end would be the "banded" end??? What do you think?? Here is a link to the wiring diagram for this diode. http://www.roadmasterinc.com/pdf/85-1409-D.pdf

From what I can tell, it looks like the OUT terminal should go to the positive????

I think the OUT terminal should go to the +12 on the relay, and the IN to the ground from your switch on the relay for the coil.

A simple Radio Shack 1N4001, or 1N4002, or 1N4003, or 1N4004 diode would work fine soldered and taped into the relay harness itself under the relay like the A/C connector diode in our cars.

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That's my attempt at drawing the diode symbol, banded end is clearly marked on most component diodes.

If you have an ohmeter when you connect the positive to the banded end of your product there and the negative to the other end it should read infinite ohms or no conduction.

When the positive lead is connected to the unbanded end and the negative is connected to the banded end it should read on the meter.

If the meter has a diode test symbol use that setting and try to determine which end is banded that way. Blocks current with the + or red lead into the banded end, black on the unbanded end, ie. NO reading or conduction.

Should be the OUT lead on your device.

Diode installed. Nothing shorted out or caught on fire so guess I did it right! Checked the diode with my meter as you suggested. Time to put some road time on the car now to see if the rpm window switch is going to work out or not.

Still want to try and make a go of using the 3rd gear wire on the trans connector if I don't like the way the RPM switch works. If I put another diode in the line that I would connect to the trans wire, think that would alleviate any spike problems?? Assuming the banded part of the diode would be pointed AWAY from the trans?

Here's something interesting...

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Fan triggering suggestion.
What about a relay with a shut off delay connected to the brake switch.

Looks like a nice project.

Good luck,

ElectraJim

Just reading around and I came across this thread. I noticed that the idea seems to involve mounting the fan on the back of the intercooler and that you guys seem to have addressed the issue of a running fan limiting airflow to around it's flow capacity. I had an alternate thought though. What if you installed a "flapper" somewhere on the intake of the scoop so air could flow in but not out. Then you could install a fan on the front of the ic scoop (the large flat area behind the radiator) blowing in. That way when the incoming airflow goes below the capability of the fan the flapper should close so the flow over the ic would always be at least what the fan is capable of. Additionally you wouldn't have to come up with a way to shut off the fan because unless you wanted to build a louvered type of check flappers for under the fan (which would be easy enough) you would have to leave it running to keep air from exiting through that opening at speed. Because there's less restricting the air through the core the fan should stop air from leaving through the front of the scoop and you should get better flow through the ic. Just a thought. james

I myself have always thought a flap would be the best bet. If you made it spring loaded so that when the air flow of the scoop overpowered the fan the "flap" would open and let the most amount of air possible over the IC.

Scott

I just read this thread....I think the easiest way would be just to do a manual switch.....when just to turn it on when needed....I had thought about this a year ago...just for cooling IC between runs and in the staging lanes...would be hooked up with my radiator fans.....the KISS approach

The key to this is having the fan running while the car is at a stop or low speeds. Why would you want to wait for the car to warm up before the intercooler fan comes on?

My fan runs once the car starts up to keep the intercooler from building up heat. The RPM switch seems to work fine for what I wanted and like I said, the manual switch gives you the option of running it all the time if you want.

I like that idea as well. Would it be mounted underside of the scoop? If so ground clearance may be an issue? Where would you mount the fan?

I posted this earlier. I'm trying to attach a pic to better describe the idea.

I got a question: aren't you just blowing hot radiator air into the IC if the fan faces the radiator?

Sorry for bumping a dated thread, but since many of us have the air intake temp sensor in the up pipe now, would it be possible to use that signal with some threshold to make the fan switch automatic with intake air temp?

I was going to make a pusher fan type with the fan under the shroud, perhaps with a custom shroud to allow clearance of the fan. I worry about pulley clearance with the rear mounted fan.